In a large-capacity inverter device configured to drive a motor for a compressor or a fan of a refrigerating and air-conditioning apparatus, a three-phase full-wave rectification type converter includes a three-phase rectifier configured to rectify a three-phase AC voltage, a smoothing capacitor including a reactor and a capacitor and being configured to smooth an output voltage of the three-phase rectifier, and an inverter circuit configured to convert the voltage of the smoothing capacitor into an AC voltage to drive a motor. In this three-phase full-wave rectification type converter, as a system for improving a power factor and a power supply current harmonic, there has been proposed a system including a step-up converter configured to step up the output voltage of the three-phase rectifier by chopping, and a switching control unit configured to control a switching element of the step-up converter. In the system, the switching control unit controls an on duty of the switching element so that a power supply current has a square wave (for example, see Patent Literature 1). In Patent Literature 1, the power supply current has a square wave, and hence as compared to a case in which a DC reactor is used immediately after the three-phase rectifier, particularly a fifth-order harmonic component of the power supply current harmonic is reduced, and thus this technology has an advantage in terms of harmonic regulation.